1. Field of the Invention
The present invention relates to a spin valve magneto-resistance effect head for reading out the information stored in a magnetic storage medium by utilizing the magneto-resistance effect of a spin valve film. Further, the present invention relates to a magnetic storage apparatus using one or more spin valve magneto-resistance effect heads according to the present invention.
2. Description of the Related Art
In recent information processing apparatuses, for example, personal computers and others, the throughput of the apparatus is considerably improved so that a large quantity of multimedia data, such as sound data, animation data, etc., can be processed at very high speed. In order to provide a large throughput, it is required to realize a magnetic storage apparatus which can freely store and read a large quantity of information, for example, from several ten Giga bytes to several hundred Giga bytes, and which can be made at a low manufacturing cost.
On the other hand, a giant magneto-resistance (GMR) effect head is provided in order to reproduce high density data which are recorded in the magnetic storage medium in the magnetic disk apparatus. Particularly, a spin valve magneto-resistance effect head has a simplified structure, and has a high sensitivity, i.e., change of resistivity, for very small magnetic field. In general, the magneto-resistance effect can be expressed by change of resistivity in response to the magnetic field. That is, this head can convert the change of the signal magnetic field generated by the magnetic storage medium to a change in resistivity. The GMR effect head can provide very large read signal.
Accordingly, research and development of the spin valve magneto-resistance effect head have been performed in many manufacturing firms in order to put this type of head into practical use in magnetic storage apparatuses.